Spatiotemporal investigation of seismicity and Coulomb stress variations prior to the 2010 M_L 6.4 Jiashian, Taiwan earthquake

The 2010 M_L 6.4 Jiashian earthquake struck southern Taiwan and caused some damage due to the strong ground shaking. Since the epicenter is located in a relatively low background seismicity area, we want to investigate seismicity rate changes associated with the Jiashian main shock by applying the region-time-length and pattern informatics algorithms. Both temporal and spatial results exhibit signatures of abnormal seismicity change related to the seismic activation and quiescence prior to the 2010 Jiashian main shock. In addition, patch of abnormal seismicity changes coincides with the region with Coulomb stress change during the same period. Our study demonstrates that the epicenter area of the 2010 Jiashian earthquake experienced a long period of seismicity rate changes and stress accumulation and thus suggests that both the variations in Coulomb stress and seismicity rate play fundamental roles in the nucleation process of impending earthquakes.